Well, it's useless but works, and it's druid only as far as I know...
Alright what you do is;
Shapeshift into anything, talk to the vendor, ask for guild crest, then change the icon into somthing.
Now you remove the shapeshift, and then change the icon into something you like, after you've done this you are done.
Now you have a tabbard sort of, it doesnt look like a tabbard only chest changes..
It goes away after a shapeshift, still free tabbard, sort of :P